The Post's editorial opposing the Rangel Amendment {Jan. 3} is seriously flawed in its premise that U.S. policy toward South Africa should be directed toward quickening peaceful change and avoiding any kindling of the explosive potential of the country. The editorial presumes that if American companies serve the cause of black economic advancement, they will contribute to peaceful change, whereas to pull out entirely would contribute to misery, militancy and civil disorder.

Such a presumption perpetuates the mistaken view that violence in South Africa is the result of black misery and lack of economic advancement. The violence in South Africa that should offend all Americans is not the potential for further Soweto riots, but the actual, omnipresent violence committed by the Afrikaner government against black humanity. The peaceful change that The Post seeks to quicken is not advanced by offering modest economic gains to a few black workers, but only by actions that must be taken by the white minority to dismantle apartheid. U.S. policy toward South Africa should be directed not toward extending the euphemistic peace of today but toward encouraging worldwide condemnation of the morally outrageous system of apartheid.

Why did The Post not express outrage at the idea of American companies financing the South African government with the taxes that the Rangel Amendment discredits? Would The Post have supported constructive engagement by U.S. companies in prewar Nazi Germany simply because a few Jews might have been offered economic advancement? It is a pity that The Post and other influential commentators do not recognize that apartheid is no less morally reprehensible than Nazism, and that the United States has a moral responsibility to dissociate itself from the violent Afrikaner regime.

MARK L. PERLIS Washington

The Post's editorial "The Rangel Amendment" is absolutely correct. The amendment, which was a backroom deal passed without a single word of public testimony, is a mistake. It attacks one of the major forces for peaceful change in South Africa.

Those who argue that the presence of U.S. companies in South Africa equals support of apartheid mistakenly believe that the withdrawal of U.S. companies will pressure the South African government into eliminating the inhumanity of apartheid. In fact, the withdrawal of U.S. companies will mean abandoning thousands of black South Africans who have come to realize that these companies are perhaps the only effective U.S. force remaining in South Africa for peaceful change.

For many of the companies, leaving South Africa would have little impact on their overall operations. They have chosen instead to remain in South Africa to help build human dignity and equal opportunity and be a contributing part of South Africa's future. For this they should be applauded -- not punished.

The Coalition on Southern Africa joins with all those who are committed to the absolute abolition of the apartheid system. The coalition, however, believes that the eradication of apartheid must not be accomplished at the expense of black South Africans. The Rangel Amendment would do just that, and we agree with The Post that it is a mistake. RICHARD L. FISHER Presiding Bishop, A.M.E. Zion Church President, Coalition on Southern Africa Washington